The Mineralocorticoid Receptor (MR) is a nuclear hormone receptor that is activated by aldosterone and regulates the expression of many genes involved in electrolyte homeostasis and cardiovascular disease. Increased circulating aldosterone increases blood pressure through its effects on natriuresis, with potentially additional effects on the brain, heart and vasculature. In addition, hyperaldosteronism has been linked to many pathophysiological processes resulting in renal and cardiovascular disease. While hyperaldosteronism is commonly caused by aldosterone-producing adenomas, resistant hypertensive patients frequently suffer from increased aldosterone levels often termed as “Aldosterone Breakthrough” as a result of increases in serum potassium or residual AT1R activity. Hyperaldosteronism and aldosterone breakthrough typically results in increased MR activity and MR antagonists have been shown to be effective as anti-hypertensive agents and also in the treatment of heart failure and primary hyperaldosteronism.
In addition, in visceral tissues, such as the kidney and the gut, MR regulates sodium retention, potassium excretion and water balance in response to aldosterone. MR expression in the brain also appears to play a role in the control of neuronal excitability, in the negative feedback regulation of the hypothalamic-pituitary-adrenal axis, and in the cognitive aspects of behavioral performance (Castren et al., J. of Neuroendocrinology, 3, 461-66 (1993)).
Eplerenone and spironolactone are two MR antagonists that have been shown to be efficacious in treating cardiovascular disease, particularly hypertension and heart failure (RALES Investigators (1999) The Effect of Spironolactone on Morbidity and Mortality in Patients with Severe Heart Failure, N. Engl. J. Med., 1999, 341(10):709-717; Pitt B, et al., EPHESUS investigator (2003) Eplerenone, a Selective Aldosterone Blocker, in Patients with Left Ventricular Dysfunction After Myocardial Infarction, N. Engl. J. Med., 348(14):1309-1321; Funder J W., (2010) Eplerenone in Chronic Renal Disease: the EVALUATE trial, Hypertens. Res., 33(6):539-40.). Moreover, multiple studies have shown that treatment with spironolactone or eplerenone significantly lower systolic blood pressure in mild-moderate, obese, systolic, PHA, and resistant hypertensive patients (Calhoun D A, et al., (2008) Effectiveness of the Selective Aldosterone Blocker, Eplerenone, in Patients with Resistant Hypertension, J. Am. Soc. Hypertens., 2008 November-December; 2(6):462-8; Huang B S, et al., (2010) Central Neuronal Activation and Pressor Responses Induced by Circulating ANG II: role of the brain aldosterone-“ouabain” pathway, Am. J. Physiol. Heart. Circ. Physiol., (2):H422-30; The RALES Investigators. (1996) Effectiveness of Spironolactone added to an Angiotensin-converting enzyme Inhibitor and a Loop Diuretic for Severe Chronic Congestive Heart Failure, (The Randomized Aldactone Evaluation Study [RALES]), Am. J. Cardiol., 1996; 78:902-907; Pitt B, et al., EPHESUS Investigators, Serum potassium and clinical outcomes in the Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS), Circulation, 2008 Oct. 14; 118(16):1643-50; Bomback A S et al., (2009), Low-dose spironolactone, added to long-term ACE inhibitor therapy, reduces blood pressure and urinary albumin excretion in obese patients with hypertensive target organ damage, Clin. Nephrol., 72(6):449-56; Williams J S, Hypertension: spironolactone and resistant hypertension, Nat. Rev. Endocrinol., 2010 May; 6(5):248-50; Nishizaka M K, et al., The role of aldosterone antagonists in the management of resistant hypertension. Curr Hypertens Rep. 2005 October; 7(5):343-7. Review; Gaddam K, et al., (2010) Rapid reversal of left ventricular hypertrophy and intracardiac volume overload in patients with resistant hypertension and hyperaldosteronism: a prospective clinical study, Hypertension, 55(5):1137-42; Zannad F, et al., (2010) Rationale and design of the Eplerenone in Mild Patients Hospitalization And Survival Study in Heart Failure (EMPHASIS-HF), Eur. J. Heart Fail., 12(6):617-22).
Evidence in preclinical models also suggest that MR antagonists would be efficacious in treating the metabolic syndrome and atherosclerosis (Takai, S. et al, (2005) Eplerenone inhibits atherosclerosis in nonhuman primates. Hypertension. 46(5):1135-9; Tirosh, A. et al., G K. (2010) Mineralocorticoid receptor antagonists and the metabolic syndrome. Curr Hypertens Rep. 2010 August; 12(4):252-7).
There is also evidence that MR antagonists may be efficacious in treating retinopathy. (Zhao et. al, (2012) Mineralocorticoid receptor is involved in rat and human ocular chorioretinopathy; The Journal of Clinical Investigation, Vol. 122(7): 2672).
There is also evidence that MR antagonists may be efficacious in treating obstructive sleep apnea, which is usually associated with cardiac disease. (Clark, D., et al., Resistant Hypertension an Aldosterone: An Update; Canadian Journal of Cardiology, (2012) Vol 28, pp 318-325).
Also, published PCT application WO 2002/17895 disclosed that aldosterone antagonists may be useful in the treatment of subjects suffering from one or more cognitive dysfunctions including, but not limited to psychoses, cognitive disorders (such as memory disturbances), mood disorders (such as depression and bipolar disorder), anxiety disorders and personality disorders.
Elevation in aldosterone levels, or excess stimulation of mineralocorticoid receptors, is linked to several physiological disorders or pathologic disease states, including Conn's Syndrome, primary and secondary hyperaldosteronism, increased sodium retention, increased magnesium and potassium excretion (diuresis), increased water retention, hypertension (isolated systolic and combined systolic/diastolic), arrhythmias, myocardial fibrosis, myocardial infarction, Bartter's Syndrome, and disorders associated with excess catecholamine levels. (Hadley, M. E., ENDOCRINOLOGY, 2nd Ed., pp. 366-81, (1988); and Brilla et al., Journal of Molecular and Cellular Cardiology, 25 (5), pp. 563-75 (1993)). Compounds and/or pharmaceutical compositions which act as MR antagonists may be of value in the treatment of any of the above conditions.
Despite significant therapeutic advances in the treatment of hypertension and heart failure, the current standard of care is suboptimal and there is a clear unmet medical need for additional therapeutic/pharmacological interventions. This invention addresses those needs by providing compounds and compositions which may be useful for the treatment or prevention of hypertension, heart failure, other cardiovascular disorders and other aldosterone disorders.